package cn.usian.controller;

import cn.usian.common.R;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.multipart.MultipartFile;

import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.UUID;

/**
 * 文件上传和下载
 */
@RestController
@RequestMapping("common")
public class CommonController {
    //获取配置
    @Value("${reggie.path}")
    private String basePath;


    /**
     * 文件上传
     * @param file
     * @return
     */
    @PostMapping("upload")
    public R upload(MultipartFile file) throws IOException {

        //原始文件名
        String originalFilename = file.getOriginalFilename();
        String suffix = originalFilename.substring(originalFilename.lastIndexOf("."));

        //使用UUID重新生成一个文件名,防止文件名称重复造成文件覆盖
        String fileName = UUID.randomUUID().toString() + suffix;

        //创建一个目录
        File dir = new File(basePath);
        //判断目录是否存在
        if(!dir.exists()){
            //目录不存在则在创一个目录
            dir.mkdirs();
        }

        File targetFile = new File(dir, fileName);
        file.transferTo(targetFile);

        return R.success(fileName);
    }


    /**
     * 文件下载
     * @param name
     * @param response
     * @throws IOException
     */
    @GetMapping("download")
    public void download(String name, HttpServletResponse response) throws IOException {
        File targetFile = new File(basePath, name);

        FileInputStream fileInputStream = new FileInputStream(targetFile);

        ServletOutputStream outputStream = response.getOutputStream();

        byte[] buf = new byte[1024];
        int length = 0;

        while((length=fileInputStream.read(buf))!=-1){
            outputStream.write(buf,0,length);
        }

        fileInputStream.close();


    }

}
